In a process of manufacturing the semiconductor device, the substrate of the semiconductor is subjected to a thermal processing to a desired depth. For example, Patent Document 1 discloses a manufacturing method of an insulated gate bipolar transistor (IGBT). The aforementioned manufacturing method will be briefly described. The diffusion region such as a base region and an emitter region, the electrode such as the emitter electrode and the gate electrode, and the insulating film such as the gate insulating film and the inter-layer insulating film are formed on the surface of the conductive silicon substrate. The back surface of the substrate is ground to have the depth of 150 μm, for example. Then the diffusion region such as the field stop layer and the collector layer are formed on the back surface of the substrate through the ion implantation and the thermal processing to form the electrode such as the collector electrode.
Patent Documents 2, 3 and 4 disclose a semiconductor device manufacturing method or a laser annealing system for irradiating two types of laser lights each having a different wavelength to the silicon substrate or the silicon film, or the laser annealing system.
Patent Document 2 discloses a semiconductor device manufacturing method and a laser annealing system for irradiating the pulsed laser light with the wavelength of approximately 500 nm in the visible optical range, and the pulsed laser light with the wavelength of approximately 250 nm in the UV range to the amorphous silicon film, for example. This makes it possible to elongate the time period for maintaining the temperature of the amorphous silicon film constant.
Patent Documents 3 and 4 disclose a semiconductor device manufacturing method and a laser irradiation system for irradiating the continuous wave (CW) laser light with the wavelength of approximately 1 μm, and the CW laser light with the wavelength of approximately 500 nm to the amorphous silicon film, for example. This makes it possible to perform the uniform laser processing or to reduce the crystalline defective region formed on the semiconductor film by eliminating the uneven irradiation.    [Patent Document 1] Japanese Patent Application Publication No. 2003-59856    [Patent Document 2] Japanese Patent Application Publication No. 2000-12484    [Patent Document 3] Japanese Patent Application Publication No. 2004-128421    [Patent Document 4] Japanese Patent Application Publication No. 2004-282060